The construction art is familiar with techniques and materials for erecting a building of expanded polystyrene (EPS) forms and reinforced concrete posts and beams. Form units are used to form substantially vertical concrete structural elements such as foundations and walls. The vertical form units are laid end to end and stacked atop each other to achieve the desired final configuration for the vertical structure. Uncured concrete is poured into the voids of the forms, forming a concrete post and beam assembly that provides structural strength and integrity. The EPS of the form provides excellent insulation for the finished wall structure.
For example, U.S. Pat. No. 4,223,501 to DeLozier discloses foamed polymeric concrete faces on a form unit which employs transverse metal connectors to support the faces and also to support finish materials. Although the foamed faces remain in place after the concrete is formed, substantially the entire interior of the form unit is filled with concrete, forming a substantially solid, uninterrupted concrete wall.
Somewhat similar art in found in U.S. Pat. No. 4,924,641 to Gibbar, Jr., which discloses polystyrene concrete wall forms made of opposite exterior polystyrene sheets separated by a matrix of polystyrene blocks. The space between blocks defines a lattice work of interior vertical and horizontal voids, which receive reinforcing bar and poured concrete. The forms are held together against bulging and separation, inside and outside, by T-shaped and L-shaped retainers joined by straps.
Another example is found in U.S. Pat. No. 4,823,534 to Hebinck, which proposes a wall structure in which EPS blocks are set on a foundation and serve both as concrete forms and as permanent pans of a building wall. The blocks define laterally spaced apart vertical post forms and, across the top course of the blocks in a wall, a horizontal beam form. Reinforcing rods are placed in the various post and beam forms and subsequently are encased in poured concrete.
Similar wall-forming art is found in U.S. Pat. No. 4,532,745 to Kinard, which adds a discrete channel member across the top of the blocks in each course. This channel member is formed of a material such as wood that can retain nails or screws, so that conventional wall surfaces can be applied in traditional ways.
The use of existing wall-forming art has been limited due to several factors. The ability of these formed concrete walls to resist buckling under vertical loads is a function of width or diameter of the vertical columns and the spacing of the columns. To use existing art for larger structures or with substantially increased loads would demand a significant increase in the amount of concrete consumed. This adversely effects the economics of the system, partially due to the cost of concrete, but largely due to the costs of handling much larger volumes of concrete. A related problem is that when proportionately more concrete is used, as compared to the quantity of EPS, the R-value of the wall system decreases.
Accordingly, there is a need for a concrete forming system in which forms of insulating material meet the design criteria that would demand varying the effective wall width; yet, do not require the cost and labor of using substantially increased quantities of concrete. Further, such a system should not sacrifice the insulation value of the insulating form material.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the building structure and method of this invention may comprise the following.